var s = window.screen;
var leftbox = document.getElementById("left_box");
var middlebox = document.getElementById("middle_box");
var myiframe = document.getElementsByClassName("my-iframe");

// 分辨率1920x1080适应大小设置
if (s.height <= 840 && s.width <= 1344) {
    leftbox.style.height = "490px";
    middlebox.style.height = "490px";
    console.log("适应屏幕分辨率1920x1080，left_box和middle_box的高度改成了490px");
    for (var i=0;i<myiframe.length;i++) {
        myiframe[i].style.height = "486px";
    }
} 
